That's deduction in the infinite case. To inductively prove TKD sucks I have to fight one TKD guy, assume the same result for n-1 TKD guys and then prove the fight result for the nth TKD guy in the general case.

I don't know but Omega made a good point. You can be a TKD fighter, have some ground skills, boxing skills, and you should be able to succeed in MMA. Just depends on who you are and if you use your TKD correctly.